$filename = "myfile"; 

print "\nThis program uses a real expression found on http://www.regular-expressions.info/unicode.html#category"; 

open( my $fh, '< :encoding(UTF-8)', $filename ) 
  or die "Cannot open $filename: $!"; 

while ( my $line = <$fh> ) { 

    if ( $line =~ /\p{Unassigned}+/ ) { 
        print "$line\n"; 
    } 
} 

print "\nThis program uses a real expression found on http://www.regular-expressions.info/unicode.html#category"; 

close $fh;